The calenders known for a suitable use are usually so constructed that a plurality of rollers are arranged vertically above each other, the rollers being rotatably mounted about their axes. In this manner is defined a stack of rollers above one another such that working slots are defined between the successive rollers for the web to be calendered. During the operation of the calender the intermediate rollers have generally the possibility to adjust within a given range in the pressure direction, as they are in force transmitting contact over their roller surface with the adjacent rollers. Furthermore it is occasionally necessary to modify the spatial position of the rollers. This can be for instance the case when the mutual gaps between the rollers must be modified for operating reasons, for example to open the slot. It is further occasionally necessary to adjust the position of the rollers when rollers having a different diameter are to be installed. For these reasons a calender is so constructed that a displacement of at least a part of the rollers in the vertical direction is possible.
It is often advantageous to select a type which permits a coarse positioning and a fine positioning of the axes of the rollers. The reason therefor is that under certain conditions, which are always to be taken into account when operating a calender, a fast opening of the roller slot can be necessary. The high speed of the opening step is then absolutely essential, short opening displacements being in this case sufficient. The situation is different for the coarse positioning of the rollers, which either has to take into account the modified roller diameters or must achieve the necessary access between the rollers. In this adjustment step it is of first importance to ensure an adjustment range greater with respect to the first one, in order to be able to carry out this adjustment step simply and securely.
Solutions are known in which the parts which carry the bearings for the rollers are vertically slidably mounted on the frame of the calender. The adjustment and the fixation of these parts is ensured in these known solutions by means of quite expensive and complicated adjustment systems, which in addition are not clearly constructed and are therefore not easily operable. Furthermore they necessitate a great number of moving machine parts with all their drawbacks.
It is an object of the present invention to achieve a method with which the positioning of the calender rollers can be ensured in the simplest and most secure manner, and in order to simplify the calender the expense of additional necessary parts must be maintained as low as possible.
This object is totally met according to the invention in a method described at the beginning wherein the vertical adjustment of the guide members is effected in such a manner that a raising or lowering movement of the roller associated to the guide member is carried out jointly with the rollers disposed below this roller and in mutual contact at least in the vicinity of the position desired for the considered roller and wherein the sliding member is driven by the raising or lowering movement of the associated roller, and in the desired position the fixation of the sliding member to be adjusted in height is effected by means of a separate fixation device supported on the support.
Further advantageous developments of the method and devices for carrying out the method will appear in the ensuing description.